1. Field of the Invention
This invention relates to a process for the production of epoxidized fatty alcohols.
2. Statement of Related Art
The conventional process for the production of epoxides from organic compounds containing at least one olefinic double bond is based on the so-called Prileschajew reaction, i.e. epoxidation with percarboxylic acids (cf. D. Swern, Organic Peroxides, Vol. II, Wiley Interscience, 1971, pages 355-533).
In the practical application of this process, the percarboxylic acids are not generally used as starting materials; instead, the corresponding carboxylic acids are combined with hydrogen peroxide to form percarboxylic acids which react in situ with the olefinic double bonds. The carboxylic acids used are, for example, formic acid, acetic acid and higher homologs thereof. Catalysts, for example sulfuric acid and other mineral acids, are often used to accelerate the reaction. Although these catalysts do accelerate the reaction, they have the disadvantage that they also initiate secondary reactions including opening the oxirane ring.
Performic acid formed in situ from formic acid and hydrogen peroxide is often used for the epoxidation of olefinically unsaturated organic compounds. This system has the advantage that the formation of the percarboxylic acid does not require a catalyst. However, in view of the fact that formic acid is a stronger acid than the other carboxylic acids used for the in situ epoxidation reaction, there is an increased tendency here toward unwanted opening of the oxirane ring (cf. D. Swern, loc. cit., pages 400-401).
The epoxidation of olefinic double bonds carried out in the absence of catalysts with performic acid formed in situ is preferably used in the production of epoxides from olefins and triglycerides containing unsaturated fatty acids (cf. German Application 30 02 861 and U.S. Pat. No. 2,485,160).
The application of the epoxidation process known from the cited prior art using performic acid formed in situ to the production of epoxidized fatty alcohols gives unsatisfactory results. In addition to the secondary reactions mentioned above, unwanted formic acid esters are formed, leaving the epoxidized fatty alcohol with an unsaturated (high) saponification value.